#!/usr/bin/env bash

clear_screen() {
    printf '\e[%sH\e[9999C\e[1J%b\e[1;%sr' \
           "$((LINES-2))" "${TMUX:+\e[2J}" "$max_items"
}

# Get a file's mime_type.
mime_type=$(file -bi "$1")

# File isn't an image file, give warning.
if [[ $mime_type != image/* ]]; then
    lf -remote "send $id echoerr 'Not an image'"
    exit
fi

w3m_paths=(/usr/{local/,}{lib,libexec,lib64,libexec64}/w3m/w3mi*)
read -r w3m _ < <(type -p w3mimgdisplay "${w3m_paths[@]}")
read -r LINES COLUMNS < <(stty size)

# Get terminal window size in pixels and set it to WIDTH and HEIGHT.
export $(xdotool getactivewindow getwindowgeometry --shell)

# Get the image size in pixels.
read -r img_width img_height < <("$w3m" <<< "5;${CACHE:-$1}")

((img_width > WIDTH)) && {
    ((img_height=img_height*WIDTH/img_width))
    ((img_width=WIDTH))
}

((img_height > HEIGHT)) && {
    ((img_width=img_width*HEIGHT/img_height))
    ((img_height=HEIGHT))
}

# Variable needed for centering image.
HALF_HEIGHT=$(expr $HEIGHT / 2)
HALF_WIDTH=$(expr $WIDTH / 2)
HALF_IMG_HEIGHT=$(expr $img_height / 2)
HALF_IMG_WIDTH=$(expr $img_width / 2)
X_POS=$(expr $HALF_WIDTH - $HALF_IMG_WIDTH)
Y_POS=$(expr $HALF_HEIGHT - $HALF_IMG_HEIGHT)

clear_screen
# Hide the cursor.
printf '\e[?25l'

# Display the image.
printf '0;1;%s;%s;%s;%s;;;;;%s\n3;\n4\n' \
    ${X_POS:-0} \
    ${Y_POS:-0} \
    "$img_width" \
    "$img_height" \
    "${CACHE:-$1}" | "$w3m" &>/dev/null

# Wait for user input.
read -ern 1

# Clear the image.
printf '6;%s;%s;%s;%s\n3;' \
    "${X_POS:-0}" \
    "${Y_POS:-0}" \
    "$WIDTH" \
    "$HEIGHT" | "$w3m" &>/dev/null

clear_screen